Systems and methods to facilitate human/robot interaction

ABSTRACT

Short range transmissions are used to identify potential interactions between warehouse workers and warehouse robots in automated warehouses. The robot can be equipped with one or more short range transmission tags, such as radio frequency identification (RFID) tags, while the warehouse worker can be equipped with a short range transmission reader, such as an RFID reader. The robot can detect a warehouse worker that is within range when the RFID tags on the robot are written to by the RFID reader. The warehouse robots and warehouse workers can also be equipped with one or more cameras to identify fiducials in the automated warehouse and to report their positions. A central control or interaction server can ensure that warehouse robots and warehouse workers are routed appropriately to avoid incidents.

BACKGROUND

Modern inventory systems, such as those in mail order warehouses, supplychain distribution centers, airport luggage systems, and custom-ordermanufacturing facilities, include a number of complex systems, includingrobots, automated shelving systems, radio frequency identification(RFID), and automated scheduling and routing equipment. Many systems,for example, comprise robots that travel to shelving systems to retrieveitems, or the shelves themselves, and return them to a central locationfor additional processing.

Automated warehouses exist that use robots, for example, to move itemsor shelves from a storage location in the warehouse to a shippinglocation (e.g., for inventory items to be boxed and shipped). It isinevitable, however, that the paths of the robots and humans working inthe warehouse will cross. Direct contact between the human workers andthe robots, however, can be problematic, and a maintenance issue for therobots.

BRIEF DESCRIPTION OF THE FIGURES

The detailed description is set forth with reference to the accompanyingfigures. In the figures, the left-most digit(s) of a reference numberidentifies the figure in which the reference number first appears. Theuse of the same reference numbers in different figures indicates similaror identical items or features.

FIG. 1 is a pictorial flow diagram of an illustrative process formaintaining a predetermined, working distance between workers and robotson an automated warehouse floor, in accordance with some examples of thepresent disclosure.

FIGS. 2A and 2B are schematic diagrams that depict components of anautomated warehouse, in accordance with some examples of the presentdisclosure.

FIG. 3 is an isometric view of a robot with multiple radio frequencyidentification (RFID) tags configured to be read by an RFID reader on aworker, in accordance with some examples of the present disclosure.

FIG. 4 is an isometric view of a worker wearing a garment with multipleRFID tags configured to be read by an RFID reader on a robot, inaccordance with some examples of the present disclosure.

FIG. 5A is a front view of a vest with multiple RFID tags, in accordancewith some examples of the present disclosure.

FIG. 5B is a front view of a baseball cap with multiple RFID tags, inaccordance with some examples of the present disclosure.

FIG. 6 is an isometric view of a cart and a robot, each with one or morecameras to provide location information to a central control, inaccordance with some examples of the present disclosure.

FIG. 7 is a top, detailed view of a fiducial comprising fiducial data,in accordance with some examples of the present disclosure.

FIG. 8 is a schematic diagram that depicts components of anotherautomated warehouse comprising a separate server, in accordance withsome examples of the present disclosure.

FIG. 9 is a flowchart depicting a method of maintaining a predetermineddistance between workers and robots in an automated warehouse usinglocation information, in accordance with some examples of the presentdisclosure.

FIG. 10A is an isometric view of a stationary robotic arm comprisingmultiple RFID tags configured to be read by an RFID reader on a workerand a circular work zone around the stationary robotic arm, inaccordance with some examples of the present disclosure.

FIG. 10B is an isometric view of a worker wearing a garment withmultiple RFID tags configured to be read by an RFID reader on thestationary robotic arm and a spherical work zone around the stationaryrobotic arm, in accordance with some examples of the present disclosure.

FIG. 10C is an isometric view of a stationary robotic arm comprisingmultiple RFID tags configured to be read by an RFID reader on a workerand a circular work zone around the worker, in accordance with someexamples of the present disclosure.

DETAILED DESCRIPTION

Examples of the present disclosure relate generally to automatedwarehouses, and specifically to one or more types of devices for use inthe warehouse to provide a virtual work zone around warehouse workersand/or warehouse robots. In some examples, the system can comprise oneor more radio frequency identification (RFID) tags and one or more RFIDreaders. In some examples, the warehouse workers can wear one or moreRFID tags to enable to robots to sense their presence. In otherexamples, the warehouse robots can comprise one or more RFID tags andthe warehouse worker can have an RFID reader. In this manner, when therobot senses an RFID reader associated with a warehouse worker iswriting to its RFID tags, the robot can sense the presence of theworker. The warehouse worker, warehouse robot, or both can also includeone or more RFID readers to identify nearby tags, verify tags, andestablish virtual work zones as necessary.

While other short range transmissions technologies besides RFID, such asBluetooth® and near field communications (NFC), could be used, oneadvantage of RFID tags is that they are inexpensive. In this manner,redundancy can be provided simply by using multiple RFID tags. Whenincorporated into a disposable garment, such as a vest or a baseballcap, for example, the whole garment can be replaced if the RFID tagshave failed, or are failing. In addition, each garment and/or each robotcan include multiple RFID tags to ensure readability from multipleangles and orientations. In this manner, regardless of the relativemotion and orientation between the robot and the worker, at least onetag can be read and identified.

To this end, as shown in FIG. 1, examples of the present disclosure cancomprise systems and methods 100 for improving efficiency and reducingmaintenance in automated warehouses by, among other things, preventingcollisions and other mishaps between workers 102 and robots 120. In someexamples, this can be achieved using virtual work zones 105 around therobots 120, the workers 102, or both. As mentioned above, in someexamples, the work zones 105 can be implemented using relatively shortrange communications, such as RFID, and readers capable of reading theseshort range communications. In this manner, when a reader on a robot 120detects the presence of an RFID tag assigned to a worker 102 (or viceversa), for example, the robot 120 can take evasive action (e.g., slowdown, stop, or reroute).

At 110, in the warehouse during normal operations, the robots 120 can berouted by a central control to various locations to, for example,retrieve merchandise, receive maintenance and/or recharging, or performmaintenance themselves (e.g., the robots 120 can take inventory imagesor provide lighting to maintenance operations). In some examples, thecentral control can determine the route for the robot from the robot'scurrent location to the next assignment (e.g., to retrieve a shelvingunit). In other examples, the central control can simply provide alocation (e.g., a grid number, row number, or GPS location within thewarehouse) to the robot 120, enabling the robot 120 to generate its ownpath.

At 125, the central control can receive a signal that a worker 102 hasentered a portion of the warehouse floor 170. In some cases, this may beto enable the worker 102 to leave for the day, for example, go to thebathroom, perform maintenance operations in the warehouse, or go on alunch break. In other cases, the worker 102 may need to enter thewarehouse to remove errant items on the warehouse floor 170 such as, forexample, inventory items that have fallen out of shelving units ortrash. In still other examples, the worker 102 may need to retrieve aninventory item manually because the shelving unit has inadvertentlybecome too heavy or imbalanced, for example, to be transported by arobot 120.

In some examples, the central control can receive a signal from asupervisor with access to the inventory control system that one or moreworkers 102 are on the warehouse floor 170. In other examples, theworkers 102 may pass by an RFID scanner, light beam sensor, motionsensor, or other sensor to signal to the central control that workers102 are present on the warehouse floor 170. In still other examples, theworkers 102 can simply enter the warehouse floor 170 and the robots 120can simply scan continuously for RFID tags associated with workers 102(as opposed to other robots 120).

The worker 102, the robot 120, or both can be equipped with RFID tagsand/or RFID readers. In some examples, the worker 102 can wear garmentsor other wearable devices that include RFID tags such as, for example, ashirt, vest, jacket, baseball cap, bracelet, necklace, ring, band,watch, etc. Similarly, the robot 120 may have one or more RFID tagslocated in various orientations (e.g., the right, left, top, bottom,forward and reverse sides). In either case, the RFID tags can besituated such that they can be read from many angles and orientations.

At 135, the robot 120 can detect the presence of a worker 102 due toRFID interaction between the robot 120 and the worker 102. In otherwords, depending on the configuration, of which several are discussedbelow, if the robot 120 (1) senses, by an RFID reader, one or more RFIDtags associated with a worker 102, or (2) senses that the RFID tags onthe robot 120 are being written to by an RFID reader associated with theworker 102, this indicates that the robot 120 is within the worker'swork zone 105 and/or that the worker 102 is in the robot's work zone105. In some examples, the tags and/or readers can simply sense thatthey are within range based on emitted signals, rather than actuallyperforming a write to the tags.

In some examples, the robot 120 can send a detection signal to thecentral control that an RFID interaction exists. The central control canthen send instructions to the robot establishing one or more work zonesaround the worker 102 and/or the robot 120. In other examples, aprocessor on the robot 120 can detect and process the RFID interaction.Regardless, in response, the robot 120 can take an appropriate “evasive”action.

In some examples, the robot 120 can simply stop until all RFID tags (orRFID readers) associated with a worker 102 are no longer in range of theRFID reader (or RFID tags) on the robot 120. In other examples, therobot 120 can detect its distance from the worker—using RFID tags,fiducials, or other means—as discussed below—to establish multiple,concentric work zones 105. In this manner, the robot 120 can try toreroute around the worker 102 upon initial contact with an outer workzone 105 a (e.g., 10 feet), for example, slow down upon contact with anintermediate work zone 105 b, and then stop upon detection of an innerwork zone 105 c (e.g., 5 feet). At 145, when the robot 120 (1) ceases todetect, with the RFID reader, RFID tags associated with the worker 102(or any worker 102), or (2) ceases to detect a reader associated withthe worker writing to its RFID tags, it can return to normal operation(e.g., continue on its route at a normal speed).

As shown in FIG. 2A, an inventory control system 200 can include aplurality of robots 120 to transport inventory items 140, shelvingunits, or inventory holders 130, or other objects for additionalprocessing. In some examples, the robots 120 can retrieve inventoryholders 130, for example, and deliver them to work stations 150. At thework stations 150, workers 102 can, for example, retrieve inventoryitems 140 from the inventory holders 130, restock the inventory holders130, or conduct inventory for the inventory holders 130, among otherthings.

As mentioned above, despite the robots 120, in some cases it maynonetheless be necessary, or desirable, for workers 102 to enter thewarehouse floor 170. This may simply enable the worker 102 to leave forthe day, go to the bathroom, perform maintenance operations in thewarehouse, or go on a lunch break. In other cases, the worker 102 mayneed to enter the warehouse floor 170 to remove errant items on thewarehouse floor 170 such as, for example, inventory items 140 that havefallen out of shelving units or trash. In still other examples, theworker 102 may need to retrieve an inventory item 140 because theshelving unit has inadvertently become too heavy or imbalanced, forexample, to be transported by a robot 120. Workers 102 may also simplyneed to leave or go to the break room via the warehouse floor 170.

Regardless of the reason, it is desirable to prevent incidents betweenworkers 102 and robots 120. To this end, examples of the presentdisclosure can comprise an inventory control system 200 for establishingwork zones 105 around the robots 120 and the workers 102. As mentionedabove, the work zones 105 can be established with a variety of shortrange transmission technologies such as, for example, Bluetooth®, nearfield communication (NFC), or RFID technology. Thus, while discussedherein with respect to RFID, it should be understood that othercommunications protocols could be used and are contemplated herein. Itshould also be noted that, while they are generally referred to as “RFIDreaders,” it is understood that RFID readers generally also have theability to write to RFID tags.

RFID technology tends to have a relatively short range—e.g., on theorder of approximately 10 feet. Within this range, RFID tags can bedetected, read, and written to by an RFID reader. As a result, thislimited range can also be used to establish approximate distancesbetween the RFID tags and the RFID reader. In addition, RFID tags can beboth passive and active. A passive RFID tag is powered byelectromagnetic induction created when the reader reads the RFID tag. Anactive RFID tag is powered by a local power source (e.g., the batteryfor the robot 120) and thus, requires less power to read and can oftenbe read over greater distances, among other things.

Based on the relatively short range of RFID tags, therefore, in someexamples, the worker 102 can wear a garment, hat, accessory, or otherwearable device that includes multiple RFID tags (e.g., in the pocketsor sewn into the garment) to enable an RFID reader on the robots 120 toidentify the worker 102. In this configuration, the robot 120 can slowdown or stop anytime it reads an RFID tag associated with a worker 102.When the robot 120 no longer detects the presence of RFID tagsassociated with the worker 102, it can continue on its normal course ofbusiness.

In other examples, the robot 120 can comprise multiple RFID tags and theworker 102 can be equipped with the RFID reader. In this configuration,detection is provided when a processor in the robot 120, and incommunication with the RFID tags on the robot 120, detects that one ormore RFID tags on the robot 120 are being written to with a readerassociated with the worker 102 (or simply that the reader is withinrange). As before, the robot 120 can slow down or stop anytime itdetects that its RFID tags are being written to by a worker's RFIDreader. In other words, in either case, the range of the RFID tags canestablish the work zone 105. In this manner, when the RFID tags arewithin the range of the reader (i.e., are detected or written to,respectively), then the robot 120 can take action (slow down, divert, orstop).

As discussed above, in some cases, the RFID tags can also providelocation or range information. In this configuration, the inventorycontrol system 200 can establish outer 105 a, intermediate 105 b, andinner 105 c work zones. In this manner, the robot 120 can escalate itsevasive action as it gets closer and closer to the worker 102. So, forexample, the robot 120 can attempt to divert around the worker 102 upondetection of the outer work zone 105 a, slow down upon detection of theintermediate work zone 105 b, and stop completely upon detection of theinner work zone 105 c.

As shown in FIG. 2B, the inventory control system 200 can furthercomprise a central control 115, a plurality of robots 120, one or moreinventory containers, pods, or holders 130, and one or more inventorywork stations 150. The robots 120 can transport the inventory holders130 between points within the warehouse floor 170 on their own, or inresponse to commands communicated by the central control 115. Eachinventory holder 130 can store one or more types of inventory items 140.As a result, the inventory control system 200 is capable of movinginventory items 140 between locations within a workspace, such as astorage facility or warehouse floor 170 to facilitate the entry,processing, and/or removal of inventory items 140 from inventory controlsystem 200 and the completion of other tasks involving the inventoryitems 140.

The central control 115 can assign tasks to the appropriate componentsof the inventory control system 200 and coordinate operation of thevarious components in completing the tasks. These tasks may relate bothto the movement and processing of inventory items and the management andmaintenance of the components of inventory control system 200. Thecentral control 115 may assign portions of the warehouse floor 170, forexample, as parking spaces for the robots 120, for the scheduledrecharge or replacement of robot 120 batteries, for the storage ofinventory holders 130, or any other operations associated with theinventory control system 200 and its various components.

The central control 115 may also select components of the inventorycontrol system 200 to perform these tasks and communicate appropriatecommands and/or data to selected components to facilitate completion ofthese operations. Although shown in FIG. 2B as a single, discretecomponent, the central control 115 may represent multiple components andmay represent, or include, portions of the robots 120, inventory holders130, or other elements of the inventory control system 200. As a result,any or all of the interaction between a particular robot 120 and thecentral control 115 that is described below may, for example, representpeer-to-peer communication between that robot 120 and one or more otherrobots 120, or may comprise internal commands based on memory in therobot 120, for example.

As mentioned above, the robots 120 can be used to move inventory holders130 between locations within the warehouse floor 170. The robots 120 mayrepresent many types of devices or components appropriate for use ininventory control system 200 based on the characteristics andconfiguration of inventory holders 130 and/or other elements ofinventory control system 200. In a particular embodiment of inventorycontrol system 200, the robots 120 can represent independent,self-powered devices, such as wheeled or tracked robots or roboticcarts, for example, configured to freely move about warehouse floor 170.Examples of such inventory control systems are disclosed in U.S. PatentPublication No. 2012/0143427, published on Jun. 7, 2012, titled “SYSTEMAND METHOD FOR POSITIONING A MOBILE DRIVE UNIT,” and U.S. Pat. No.8,280,547, issued on Oct. 2, 2012, titled “METHOD AND SYSTEM FORTRANSPORTING INVENTORY ITEMS,” the entire disclosures of which areherein incorporated by reference.

In other examples, the robots 120 can comprise track guided robotsconfigured to move inventory holders 130 along tracks, rails, cables, acrane system, or other guidance or support elements traversing thewarehouse floor 170. In this configuration, the robot 120 may receivepower, communications, and/or support through a connection to guidanceelements such as, for example, a powered rail, slot, or track.Additionally, in some examples of the inventory control system 200, therobot 120 may be configured to utilize alternative conveyance equipmentto move within warehouse floor 170 and/or between separate portions ofwarehouse floor 170.

Additionally, the robots 120 may be capable of communicating with thecentral control 115 to receive tasks, inventory holder 130 assignments,transmit their locations or the locations of other robots 120, orexchange other suitable information to be used by central control 115 orrobots 120 during operation. The robots 120 may communicate with centralcontrol 115 using, for example, wireless, wired, or other connections.In some examples, the robots 120 may communicate with central control115 and/or each other using, for example, 802.11 specification wirelesstransmissions (e.g., a/b/g/n), Bluetooth, radio frequency (RF), InfraredData Association (IrDA) standards, or other appropriate wirelesscommunication protocols.

In other examples, such as in an inventory control system 200 usingtracks, the tracks or other guidance elements (e.g., slots or rails)along which robot 120 moves may be wired to facilitate communicationbetween robot 120 and other components of inventory control system 200.Furthermore, as noted above, the robot 120 may include components of thecentral control 115 such as, for example, processors, modules, memory,and transceivers. Thus, for the purposes of this description and theclaims that follow, communication between central control 115 and aparticular robot 120 may also represent communication between componentswithin a particular robot 120. In general, the robots 120 can bepowered, propelled, and controlled in many ways based on theconfiguration and characteristics of a particular inventory controlsystem 200.

The inventory holders 130 are used to store inventory items and caninclude additional features as part of the inventory control system 200.In some examples, each of the inventory holders 130 can include multipledividers to create multiple bins or bays within the inventory holders130. In this configuration, each inventory holder 130 can store one ormore types of inventory items 140 in each bin or bay (e.g., eachinventory holder 130 may store the same inventory item 140 in all binsor bays, or different inventory items 140 in each bin or bay, or have nobins or bays and store just one type of item 140). Additionally, inparticular examples, inventory items 140 may also hang from hooks orbars within, or on, the inventory holders 130. In general, the inventoryholders 130 may store inventory items 140 in any appropriate mannerwithin the inventory holders 130 and/or on the external surface of theinventory holders 130.

The inventory holders 130 can be configured to be carried, rolled,and/or otherwise moved by the robots 120. In some examples, theinventory holders 130 may also provide propulsion to supplement thatprovided by robot 120 when moving multiple inventory holders 130, forexample. Additionally, each inventory holder 130 may include a pluralityof sides, and each bin or bay may be accessible through one or moresides of the inventory holder 130. For example, in a particularembodiment, the inventory holders 130 include four sides. In such anembodiment, bins or bays located at a corner of two sides may beaccessible through either of those two sides, while each of the otherbins or bays is accessible through an opening in one of the four sidesand a free-standing inventory holder 130 with no bins or bays may beaccessible via all four sides. The robot 120 may be configured to rotateinventory holders 130 at appropriate times to present a particular faceand the bins, bays, shelves or dividers associated with that face to anoperator or other components of inventory control system 200 tofacilitate removal, storage, counting, or other operations with respectto inventory items 140.

In particular examples, the inventory control system 200 may alsoinclude one or more inventory work stations 150. Inventory work stations150 represent locations designated for the completion of particulartasks involving inventory items. Such tasks may include the removal ofinventory items 140, the addition, or restocking, of inventory items,the counting of inventory items 140, the unpacking of inventory items140 (e.g. from pallet- or case-sized groups to individual inventoryitems), the consolidation of inventory items 140 between inventoryholders 130, and/or the processing or handling of inventory items 140 inany other suitable manner. The work stations 150 may represent both thephysical location and also any appropriate equipment for processing orhandling inventory items, such as work benches, packing tools andsupplies, scanners for monitoring the flow of inventory items in and outof inventory control system 200, communication interfaces forcommunicating with central control 115, and/or any other suitablecomponents. Inventory work stations 150 may be controlled, entirely orin part, by human operators or may be partially or fully automated.

In operation, the central control 115 selects appropriate components tocomplete particular tasks and transmits task assignments 118 to theselected components. These tasks may relate to the retrieval, storage,replenishment, and counting of inventory items and/or the management ofrobots 120, inventory holders 130, inventory work stations 150, andother components of inventory control system 200. Depending on thecomponent and the task to be completed, a particular task assignment 118may identify locations, components, and/or actions associated with thecorresponding task and/or any other appropriate information to be usedby the relevant component in completing the assigned task.

In particular examples, the central control 115 generates taskassignments 118 based, in part, on inventory requests that centralcontrol 115 receives from other components of inventory control system200 and/or from external components in communication with centralcontrol 115. For example, in particular examples, an inventory requestmay represent a shipping order specifying particular inventory itemsthat have been purchased by a customer and that are to be retrieved frominventory control system 200 for shipment to the customer. The centralcontrol 115 may also generate task assignments 118 in response to theoccurrence of a particular event (e.g., in response to a robot 120requesting a space to park), according to a predetermined schedule(e.g., as part of a daily start-up or cleaning routine), or at anyappropriate time based on the configuration and characteristics ofinventory control system 200.

The central control 115 may, in some cases, communicate task assignments118 to a robot 120 that include one or more destinations for the robot120. In this vein, the central control 115 may select a robot 120 basedon the location or state of the robot 120, an indication that the robot120 has completed a previously-assigned task, a predetermined schedule,and/or any other suitable consideration. For example, the taskassignment may define the location of an inventory holder 130 to beretrieved, an inventory work station 150 to be visited, a storagelocation where the robot 120 should park until receiving another task,or a location associated with any other task appropriate based on theconfiguration, characteristics, and/or state of inventory control system200, as a whole, or individual components of inventory control system200.

As part of completing these tasks, the robots 120 may dock with variousinventory holders 130 within the warehouse floor 170. The robots 120 maydock with inventory holders 130 by connecting to, lifting, and/orotherwise interacting with inventory holders 130 such that, when docked,the robots 120 are coupled to the inventory holders 130 and can moveinventory holders 130 within the warehouse floor 170. While thedescription below focuses on particular examples of robots 120 andinventory holders 130 that are configured to dock in a particularmanner, alternative examples of robots 120 and inventory holders 130 maybe configured to dock in any manner suitable to allow robots 120 to moveinventory holders 130 within warehouse floor 170.

Components of inventory control system 200 may provide information tothe central control 115 regarding their current state, the state ofother components of inventory control system 200 with which they areinteracting, and/or other conditions relevant to the operation ofinventory control system 200. This may allow central control 115 toutilize feedback from the relevant components to update algorithmparameters, adjust policies, or otherwise modify its decision-making torespond to changes in operating conditions or the occurrence ofparticular events. In addition, while central control 115 may beconfigured to manage various aspects of the operation of the componentsof inventory control system 200, in particular examples, the componentsthemselves may also be responsible for some decision-making relating tocertain aspects of their operation, thereby reducing the processing loadon central control 115.

In some examples, the warehouse floor 170 floor can also comprise aplurality of markers, or fiducials 175, to enable the robots 120 toestablish their location in the warehouse. Because the robots 120 aregenerally low enough to travel under inventory holders 130 (i.e., to beable to lift them), in some examples, the fiducials 175 can alsocontinue under the inventory holders 130, substantially spanning theentire floor. In some examples, the area between the fiducials 175 candefine grid areas 175 a with a fiducial 175 at each corner. Whenattempting to locate a particular inventory holder 130, therefore, therobot 120 can locate the fiducial 175, or grid 175 a, associated withthe inventory holder's location by scanning the floor with a downwardfacing scanner or camera and then confirm that it is in the rightlocation by scanning an identifier, e.g., a 2D or 3D bar code, an RFIDtag, or other identifier, on the bottom of the inventory holder 130 withan upward facing scanner or camera, for example. In some examples, theinventory holder 130 and/or the fiducials 175 can include 2D or 3D barcodes, an RFID tag, or other identifiers.

As shown in FIG. 3, examples of present disclosure can comprise a system300 for maintaining a predetermined, or threshold, working distancebetween workers 102 and robots using RFID, or other short-rangetransmission technologies. In some examples, the robot 120 can beequipped with one or more passive or active RFID tags 305 and the worker102 can be equipped with an RFID reader 310. In some examples, the RFIDtags 305 on the robot 120 can comprise active RFID tags 305 (i.e., tagswith a power source) and can be powered by a battery 320 on the robot120 (e.g., the battery that powers the robot 120 or a separate battery).The robot 120 can also comprise a processor 315 in communication withthe one or more RFID tags 305 to monitor the status of the RFID tags305.

In this manner, as the robot 120 travels through the warehouse, if theRFID tags 305 are sensed, scanned, or written to, by the worker's RFIDreader 310, the RFID tag 305 can send a signal to the processor 315reporting same. The robot 120 can then take evasive action because itsenses it is within range of the worker 102. In other words, because therobot 120 must be within range of the RFID reader 310 for the RFID tag305 to sense or be written to by the RFID reader 310, the robot 120knows it is within the work zone 105. As mentioned above, the robot 120can then attempt to reroute, slow down, or stop, as appropriate.

Of course, the predetermined, or threshold, distance to be maintainedbetween the worker 102 and the robot 120 can vary widely depending onthe size of the warehouse floor 170, the number of workers 102 androbots 120, and the level of activity at a particular time on thewarehouse floor 170. If, for example, the warehouse floor 170 isparticularly large, maintaining a relatively large work zone 105 (e.g.,25 feet) may be easier to manage and require less system 300 resources,while having little impact on the efficiency of the inventory controlsystem 200. On smaller warehouse floors 170 or inventory control systems200 with a large number of robots 120 or very busy warehouse floors 170,it may be desirable to reduce the size of the work zone (e.g., to 10feet) to reduce the effect on robots 120 retrieving inventory holders130 and performing other duties. Of course, many predetermined distancescan be chosen to suit many warehouse and traffic configurations.

In some examples, the robot 120 can also be equipped with an RFID reader310. The RFID reader 310 can be in communication with the processor 315and can periodically scan for RFID tags 305 that are within range. Inthis manner, the robot 120 can run self-checks on the RFID tags 305located on the robot 120 (i.e., its own RFID tags 305). In otherexamples, the RFID tags 305 on the robot 120 can be checked when therobot 120 docks to be recharged (approximately once per hour) or isotherwise maintained.

If one or more RFID tags 305 on the robot 120 fails, the robot 120 canreport the failure to the central control 115. The central control 115can then schedule maintenance for the robot 120 to have the failed RFIDtags 305 replaced. Some, or all, of the RFID tags 305 can be replacedwhen any RFID tags 305 fail. In other words, because RFID tags 305 areinexpensive, it may be prudent to simply replace them all. In otherexamples, the central control 115 may replace the RFID tags 305 onlywhen a certain number or percentage of RFID tags 305 fail, or when thenumber of operating RFID tags 305 out of the total number of RFID tags305 reaches a predetermined level (e.g., based on the desired level ofredundancy).

Because RFID tags 305 are relatively inexpensive (less than $1), therobot 120 can be equipped with multiple RFID tags 305 to provideredundancy. In this manner, a significant number of RFID tags 305 canfail without posing a concern because a significant number of RFID tags305 remain operational. In some examples, the processor 315 and/or thecentral control 115 can monitor the locations of failed RFID tags 305 toensure that at least one RFID tag 305 in each orientation (e.g., atleast one RFID tag 305 on each face of the robot 120) is operational.

Similarly, as shown in FIG. 4, examples of present disclosure cancomprise another system 400 for maintaining a predetermined distancebetween workers 102 and robots using RFID, or other short-rangetransmission technologies. In some examples, the worker 102 can wear agarment 405 or other wearable device, such as a vest, a hat, orcoveralls that includes one or more RFID tags 305. In some examples, theRFID tags 305 can comprise surface RFID tags 305 a that can be sewn oradhered, for example, to the surface of the garment 405. In otherexamples, the RFID tags 305 can be embedded RFID tags 305 b that aresewn into, or otherwise incorporated into the garment 405. Embedded RFIDtags 305 b may improve the aesthetics of the garment 405, for example,or may simply provide some protection to the RFID tags 305 from abrasionor other damage. In this configuration, the RFID reader 310 on the robot120 constantly polls for RFID tags 305 at a predetermined interval(e.g., once every second, once every 0.5 seconds) that are within range.When the robot 120 receives a return from a RFID tag 305 associated witha worker 102, the robot 120 can take evasive action.

As before, initially the robot 120 can attempt to deviate from itscurrent route slightly to avoid the worker 102. If the worker 102remains in range, however, or the signal gets stronger, for example, therobot 120 can slow down and eventually stop, as necessary. The robot 120can remain in this mode of operation until the RFID reader 310 on therobot 120 no longer detects any RFID tags 305 associated with the worker102 (or any worker 102) and then return to normal operation.

To provide additional redundancy, the robot 120 can also include one ormore RFID tags 305. The RFID reader 310 on the robot 120 can then scanthese RFID tags 305 to ensure that the RFID reader 310 is functioningproperly. If the RFID reader 310 on the robot 120 fails to detect apredetermined number or percentage of RFID tags 305 on the robot 120,the robot 120 can alert the central control 115. The central control 115can then take the robot 120 offline, enter a maintenance request, orstop the robot 120 immediately, among other things.

In some examples, the system 400 can also include an RFID reader 310that can be worn by the worker 102 to ensure that a sufficient number ofthe RFID tags 305 in the garment 405 or other wearable device arefunctioning properly to meet system guidelines. In some examples, theRFID reader 310 can further comprise an indicator 325. In some examples,the indicator 325 can comprise a transceiver (e.g., a wirelesstransceiver) to communicate with the central control 115 to report ahigh number of failed RFID tags 305. The central control 115 can thenprovide a message to the worker 102 or a supervisor, for example, thatthe worker 102 needs a new garment 405 or other wearable device. Inother examples, the indicator 325 can comprise a light or an audiblealarm to directly alert the worker 102 of the failure. The worker 102can then retrieve a new garment 405 or other wearable device.

Regardless of the configuration (i.e., FIG. 3 or FIG. 4), in someexamples, the systems 300, 400 can also use fiducials 175 in thewarehouse floor 170 to establish appropriate work zones 105 based, atleast in part, on the range of the RFID readers 310 and tags 305 in thesystem 300, 400. In other words, in some examples, the fiducials 175 canalso include RFID tags 305 to provide location information to RFIDreaders 310 on the robots 120 and/or workers 102 to establish the rangeof the RFID readers. When the RFID reader reports to the central control115, for example, it can include all of the fiducials 175 it can “see”at any given time. Based on location information associated with thereported fiducials 175, therefore, the central control 115 can determinethe range of a particular RFID reader 310 or the average range of allRFID readers 310 in the system 300, 400, for example.

The central control 115 can then use this information, in part, toestablish the radius used for the outer work zone 105 a. The ranges ofvarious RFID components 305, 310 can vary widely based on, for example,atmospheric conditions, local interference, placement, battery chargelevels, and angle of incidence between the reader and tag. In additionto RFID range, the size of work zones 105 can also be based on thenumber of robots 120 and/or workers 102 on the warehouse floor 170, thetravel speed of the robots 120, and the size of the warehouse floor 170,among other things. Because some of these variables can change, in someexamples, the system 300, 400 can periodically reset work zones 105based on current conditions.

In some examples, if the range of the RFID readers 310 and/or RFID tags305 falls below a predetermined threshold, on the other hand, the system300, 400 can instruct one or more of the robots 120 to take evasiveaction. In other words, if the range for one or more RFID components305, 310 in the system 300, 400 fall below a predetermined distance(e.g., 10 feet), then an appropriate work zone 105 may not be possibleor practical. To prevent unwanted interactions between robots 120 andworkers 102, therefore, the system 300, 400 can instruct some or all ofthe robots 120 to stop or slow down until the range issue can berectified (e.g., with new batteries).

As shown in FIGS. 5A and 5B, the system 400 can include a vest 505, hat510, coveralls, belts, or other item of clothing (collectively,“garment”) that can be easily worn and can include a plurality of RFIDtags 305. In some examples, as shown, the garment can include RFID tags305 arranged in multiple orientations and locations to enable the RFIDtags 305 on the garment to be detected by RFID readers 310 regardless oftheir relative positions. In other words, the RFID readers 310 candetect at least one tag 305 regardless of whether the worker 102 iswalking away or towards the robot 120 and regardless of the worker'srelative position to the robot (e.g. in front, behind, or to either sideof the robot 120).

Using multiple RFID tags 305 in each garment also increases theredundancy of the system, such that multiple RFID tag 305 failures arerequired before the effectiveness of the garment is significantlyaffected. In some examples, the garment can be disposable such that whenthe number of RFID tag 305 failures reaches a predetermined number orpercentage, for example, the worker 102 can simply throw the vest 505 orhat 510 away and retrieve a new one. In some examples, the vest 505and/or hat 510 can also include reflective tape or other featuresenabling the garment to serve multiple purposes.

In some examples, the garment can comprise RFID tags 305 a mounted onthe surface. In other embodiments, the garment can comprise RFID tags305 b embedded (e.g., sewn into) the garment. In still otherembodiments, the garment can include multiple types of RFID tags 305 a,305 b such as, for example, passive, active, and semi-active RFID tags305.

In still other embodiments, as shown in FIG. 6, the robot 120 cancomprise an onboard imaging device, or camera 605, and a transceiver610. As the robot 120 traverses the warehouse floor 170, the camera 605can detect and identify fiducials 175 on the warehouse floor 170. Therobot 120 can communicate with the central control 115 using thetransceiver 610 and can provide, for example, location, direction, andspeed information.

As shown in FIG. 7, the fiducials 175 can comprise, for example,stickers or plaques attached to the warehouse floor 170. In someexamples, the fiducials 175 can provide their location in the warehouse(e.g., they can include a coordinate, row and column number, gridnumber, GPS location, or other information). In some examples, thelocation of the fiducial 175 can be printed on the fiducial 175 and canbe read by the camera 605 on the robot 120.

In other examples, as shown in detail in FIG. 7, the fiducials 175 canalso comprise additional fiducial data 705. The fiducial data 705 cancomprise, for example, a fiducial identification number (ID) 175 b(e.g., “fiducial 186143a”). In some examples, the robot 120 can read thefiducial ID 175 b with the camera 605, or other suitable device, and cancross-reference the fiducial ID 175 b with an onboard database toestablish its location. In other embodiments, the central control 115can include a fiducial database and the robot 120 can transmit thefiducial ID 175 b to the central control 115 and the central control 115can provide the location of the fiducial 175 to the robot 120.

In other examples, the fiducial data 705 can also comprise, for example,a bar code 175 c and/or an RFID tag 305, among other things, that can beread by the robot 120. In some examples, the bar code 175 c or RFID tag305 can have embedded location information to directly provide locationinformation to the robot. In other embodiments, as discussed above, therobot 120 can read or scan the bar code 175 c or RFID tag 305, transmitthe fiducial data 705 to the central control, and receive locationinformation for the fiducial 175 from the central control 115 todetermine the location of the robot 120 on the warehouse floor 170.

Referring back to FIG. 6, in some examples, the worker 102 can also beequipped with one or more cameras 605. In some examples, the worker 102can wear a camera 605 on a headband, armband, or a necklace. In otherexamples, the worker 102 can utilize a cart 615 equipped with one ormore cameras 605. The cart 615 can also include one or more carryingtrays 630 to enable the worker 102 to, for example, retrieve merchandisefrom inventory holders 130, carry tools for maintenance operations, orretrieve trash or inventory items 140 from the warehouse floor 170. Likethe robot 120, therefore, as the worker 102 moves across the warehousefloor 170, the camera(s) 605 can identify and report the fiducials 175proximate the cart 615.

The cart 615 can also comprise a processor 650 and a transceiver 655 totransmit the location of the cart 615 to the central control 115. Insome examples, the processor 650 can perform some or all of the imageprocessing (e.g., parsing) required for the images from the one or morecameras 605 to reduce bandwidth between the cart 615 and the centralcontrol 115. Thus, the central control 115 can receive periodic updatesfrom both the robot 120 and the cart 615 regarding their location and/orincluding imagery or data related to imagery from the one or morecameras 605 on the robots 120 and cart 615. This can enable the centralcontrol 115 track the locations of the robots 120 and the cart 615 andinstruct the robot 120 to take evasive action when necessary. In somecases, the central control 115 can track the robot 120 and the cart 615,determine when the robot 120 and the cart 615 are on a collision course,and reroute the robot 120 as necessary, for example.

It is, of course, possible that the worker 102 could walk away from thecart 615, rendering their location unknown to the central control 115.In other words, when the worker 102 walks away from the cart, thecameras 605 on the cart 615 provide the central control 115 with thelocation of the cart 615, but not the location of the worker 102. As aresult, in some examples, the system 600 can also comprise a “tether”625 between the cart 615 and the worker 102.

In some examples, the tether 625 can be a physical tether 625, similarto those used on boats and jet skis, for example, and can comprise aphysical connection between the cart 615 and the worker 102. The tether625 can comprise, for example, a lariat or harness around the worker'swrist, or attached to the worker's clothes, and then attached to aswitch on the cart 615. In other examples, the tether 625 can comprisean electromechanical connection between the cart 615 and the worker 102.In some examples, the handle 635 of the cart 615 can comprise one ormore electrical contact pads for measuring the temperature, resistance,or capacitance of the handle 635, for example. In this configuration,the central control 115 can determine that the worker 102 has one orboth hands on the handle.

In still other embodiments, the tether 625 can comprise what isessentially an “electromagnetic” tether. In other words, using RFIDtechnology, or other short range link, in a similar manner to thatdiscussed above, the tether 625 can determine whether the worker 102 iswithin a certain distance of the cart 615. So, for example, as discussedabove, the system 600 can include a garment for the worker 102 (e.g., avest 505) comprising one or more RFID tags 305 and the cart 615 cancomprise a RFID reader 310. When the worker 102 is within range of theRFID reader 310, therefore, the tether 625 can be considered “latched,”and the system 600 can operate normally.

If the worker 102 is out of range of the RFID reader 310, on the otherhand, the tether 625 can be considered “unlatched,” send an unlatchedsignal to the central control 115, which may require the central control115 to stop all robots 120 in the warehouse, or in a portion of thewarehouse, until the worker 102 can be “found.” In other words, if thetether 625 is unlatched, the location of the worker 102 on the warehousefloor 170 is essentially unknown. If this is the case, the centralcontrol 115 cannot accurately route robots 120 around the worker 102 andmay have no choice but to shut down all of the robots 120. In somecases, when the worker 102 returns to the cart 615, the tether 625 canautomatically “relatch,” send a relatch signal to the central control115, and normal warehouse operations can resume. In some examples, toprevent a total shutdown, the system 600 can include a secondarylocation system using, for example, RFID, proximity sensors, infraredcameras, or facial recognition, to locate the worker 102. In a preferredexample, workers 102 can simply be trained to stay within range of theircart 615 at all times.

In some examples, a similar system 600 can be used in a work station150. In other words, while the worker 102 in a work station 150 istheoretically stationary, in some instances, the worker 102 may need totemporarily leave the bounds of the work station 150 to retrieve adropped item, for example. Thus, while a “permanent” work zone 105 mayexist with respect to the work station 150 (to keep robots 120 fromdriving through the work station 150), if the worker 102 leaves the workstation 150, the robots 120 may need to take additional evasive action.

To this end, if the system 600 detects that the worker 102 has left thework station 150, the system 600 can instruct one or more robots 120 toslow down or stop, for example. In this situation, the tether 625 cancomprise, for example, a light curtain, light beam, or proximity sensorto determine when the worker 102 leaves the work station 150. In someexamples, the work station 150 can also comprise an additional RFIDreader 310 to provide additional range information to the centralcontrol 115.

In some examples, as shown in FIG. 8, it may be desirable to have awarehouse system 800 with separate management and interaction systems.In other words, the system 800 can comprise a central control 115 formanaging overall routing and work flow and a second server 805 formanaging worker 102/robot 120 interactions. In this manner, a higherlevel of redundancy can be provided and each system 100, 800 can beoptimized for the purpose at hand.

To this end, in addition to the redundancy provided by the use ofmultiple RFID tags 305 and RFID readers 310, as discussed above, in someexamples, the work zones 105, robots 120, and workers 102 can bemonitored and managed by a dedicated interaction server 805. In thisconfiguration, the central control 115 can handle the routing andscheduling of robots 120 during normal operation—e.g., retrievinginventory holders 130 and delivering them to work stations—while theinteraction server 805 can monitor workers 102 and robots 120 solely forthe purpose of preventing incidents. In this manner, the operations ofthe robots 120 and the workers 102 are not in conflict, reliability isincreased via redundant communications and control systems, and downtimeand maintenance is reduced by reducing the number of robot 120/worker102 interactions, among other things.

In some examples, the robots 120 can be in communication with thecentral control 115 via a first, dedicated communications network 810and in communication with the interaction server 805 via a second,dedicated communications network 815. Both networks can comprise, forexample, wireless LANs (e.g., 802.11x networks), or other suitablenetworks. In some examples, the interaction server 805 and secondnetwork 815 can also be on dedicated internet, power, or networkconnections, as necessary.

In some examples, therefore, the second network 815 can also comprise anetwork with a higher level of reliability and/or security than thefirst network 810. The second network 815 may also be able to overridethe first network 810. In other words, if the interaction server 805determines that an incident between a worker 102 and a robot 120 isimminent, the interaction server 805 can send a command to the robot 120regardless of whether the robot 120 is currently receiving a commandfrom the central control 115. In this case, the robot 120 can ignore thecommand from the central control 115, take evasive action, if necessary,and then reconnect with the central control 115 when the worker is nolonger proximate the robot 120.

As shown in FIG. 9, examples of the present disclosure can also comprisea method for using the location information from the fiducials 175 tomaintain a predetermined distance between workers and robots. At 905, aworker enters the floor of the warehouse. As mentioned above, there areseveral reasons the worker may need or want to enter the warehousefloor.

At 910, the aforementioned camera(s) can begin to provide locationinformation for the worker to the central control or the interactionserver. In some examples, the cameras can be located on the worker or ona cart used by the worker and can be activated manually by the worker,or automatically upon entering the warehouse. In some examples, the cartcan comprise a motion sensor, for example, which can signal the camerasand transceiver to begin sending location information. In still otherexamples, the system can include light beams, sensors, infrared sensors,motions sensors, or other means to detect workers in the warehouse. Thelocation information from the worker can be updated periodically at aconstant or variable rate, which can change based on the number ofworkers and robots in motion in the warehouse, the level of activity inthe warehouse, and other factors.

At 915, the central control or interaction server can also receivelocation information from a plurality of robots on the warehouse floor.In the case of the central control, the location information may alreadybe provided automatically as part of the inventory management system. Inother cases, the interaction server, for example, may begin pollingrobots for location information upon receiving location information fromthe worker or upon receiving a notification that a worker has enteredthe warehouse (e.g., from a motion sensor in the warehouse). Again, thelocation information from the robot can be updated periodically at aconstant or variable rate, which can change based on the number ofworkers and robots in motion in the warehouse, the level of activity inthe warehouse, and other factors.

At 920, based on the location information from the worker, the systemcan establish a virtual work zone around the worker. As discussed above,this can comprise a single work zone at a predetermined distance (e.g.,10 feet), or can comprise a multi-level work zone within which the levelof evasive action is escalated as the robot gets closer to the worker.At 925, the system can determine whether the robot is within the workzone based on the location information. If the robot is not within thework zone, the system can simply wait for the next location update fromthe worker, at 910, and the robot, at 915.

At 930, if the robot is within the work zone, on the other hand, thesystem (i.e., the central control or interaction server) can send acommand to take evasive action. In some examples, such as with a singlelayer work zone, the system can simply command the robot to stop. Inother examples, the system can take escalating evasive action—e.g.,reroute→slow down→stop—as the robot enters an outer, intermediate, andinner work zone, respectively. In this manner, when a robot and a workerare merely traveling close to one another or at an oblique angle, aslight deviation can enable the robot to miss the worker with littleinterruption to the system. If the worker and the robot are on acollision course, on the other hand, the robot may need to simply stopand yield the right-of-way to the worker. At 935, the system cancontinue to monitor and control the robots, as necessary, until theworker leaves the warehouse floor.

In yet other examples, the robot can switch to a differentnavigation/sensing system. In other words, part of the evasive actioncan comprise switching over to a sensor with higher resolution, such asa high resolution video camera, to enable more precise robotmaneuvering. In other examples, the robot can switch over to a second,more precise navigation system or algorithm. In this manner, rather thansimply moving from one fiducial to the next along a travel direction,the robot can utilize additional inputs to enable the robot toaccurately reroute, slow, or stop, as necessary.

In still other examples, the systems described herein can also be usedto provide a work zone 105, 1005 around a stationary robotic arm 1020(FIGS. 10A and 10B) or around a worker 102 in proximity to the roboticarm 1020 (FIG. 10C). A stationary robotic arm 1020 may be used in thewarehouse, for example, to unload boxes, perform maintenance, or handleother tasks that can be completed in a relatively consistent area. Inother examples, the robotic arm 1020 may be moveable, but not mobile perse, to perform jobs in a limited number of places, for example, or forlonger work intervals. Regardless, while the robotic arm 1020 is notmobile, the robotic arm 1020 nonetheless has a circle or sphere ofmotion, depending on its capabilities, within which it operates. Directcontact between workers 102 and the robotic arm 1020 can be problematic,reduce efficiency, and increase maintenance for the robotic arm 1020.

To this end, as with the mobile robots 120 discussed above, it can beuseful to establish one or more work zones 1005, which can includecircles 105 (FIG. 10A) or spheres 1005 (FIG. 10B). As before, in someexamples, the system 1000 can include an outer work zone 105 a, anintermediate work zone 105 b, and an inner work zone 105 c. This canenable the robotic arm 1020 to take one or more evasive actions as aworker 102 (or robot 120) enters the work zone 105. In some examples,the system 1000 can use multiple spherical work zones 1005

In some examples, the system 1000 may slow down the robotic arm 1020when a worker 102 enters the outer work zone 105 a. The system 1000 maythen apply brakes and/or assume a predetermined position when a worker102 enters the intermediate work zone 105 b. Finally, the system 1000may remove power from the robotic arm 1020 when a worker 102 enters theinner work zone 105 c. In some examples, the robotic arm 1020 may putobjects down on the floor, or other work surface, and wait for theworker 102 to leave the work zone 105 or take other additional actionsduring this process.

As with the systems 300, 400, 600 discussed above, the system 1000 cancomprise one or more RFID readers/tags and/or imaging devices tomaintain a work zone 1005 around the robotic arm. In some examples, asshown in FIG. 10A, the system 1000 can comprise one or more RFID tags305 disposed on the robotic arm 1020 and an RFID reader 310 on theworker 102 to detect an RFID interaction. In other examples, as shown inFIG. 10B, the system 1000 can utilize multiple surface mount 305 a, orembedded 305 b, RFID tags on the worker 102 and an RFID reader 1030 onthe robotic arm 1020 to detect RFID interactions. In still otherexamples, the robotic arm 1020 can comprise one or more imaging devices1025 to provide information related to the position of the robotic arm1020 and/or work zones 105, 1005.

While several possible examples are disclosed above, examples of thepresent disclosure are not so limited. For instance, while a system formaintaining a predetermined distance between robots and workers in anautomated warehouse is disclosed, the system could also be used anytimehumans and automated machines or fixed robotic systems interact. Inaddition, the location and configuration used for various features ofexamples of the present disclosure such as, for example, the locationand configuration of RFID tags and readers, the types of cameras orother sensors used, and the layout of the warehouse can be variedaccording to a particular warehouse, location, or robot that requires aslight variation due to, for example, size or power constraints, thetype of robot required, or regulations related to transmissioninterference, for example. Such changes are intended to be embracedwithin the scope of this disclosure.

The specific configurations, choice of materials, and the size and shapeof various elements can be varied according to particular designspecifications or constraints requiring a device, system, or methodconstructed according to the principles of this disclosure. Such changesare intended to be embraced within the scope of this disclosure. Thepresently disclosed examples, therefore, are considered in all respectsto be illustrative and not restrictive. The scope of the disclosure isindicated by the appended claims, rather than the foregoing description,and all changes that come within the meaning and range of equivalentsthereof are intended to be embraced therein.

What is claimed is:
 1. A method to maintain a threshold distance between a worker and a robot in a workspace, the method comprising: receiving, at a server from an imaging device associated with the robot, first location information for the robot in the workspace at a first time, wherein the server is external to the worker and the robot; receiving, at the server from an imaging device associated with the worker, second location information for the worker in the workspace at the first time; designating, with the server, a work zone encompassing at least the worker and comprising at least an inner barrier and an outer barrier; calculating, with the server, a distance between the robot and the worker based at least in part on the first location information for the robot and the second location information for the worker; and transmitting, from the server to the robot, an instruction to take evasive action based at least in part on the robot crossing the outer barrier; wherein the first location information for the robot comprises first fiducial data from a first fiducial, the first fiducial proximate to the robot at the first time; wherein the second location information for the worker comprises second fiducial data from a second fiducial, the second fiducial proximate to the worker at the first time.
 2. The method of claim 1, wherein the first fiducial data from the first fiducial comprises a bar code received from the imaging device associated with the robot; and wherein the bar code comprises at least a location of the first fiducial.
 3. The method of claim 1, wherein the evasive action comprises at least one of rerouting, slowing down, or stopping the robot.
 4. The method of claim 1, further comprising: transmitting, from the server to the robot, another instruction to take a different evasive action based at least in part on the robot crossing the inner barrier.
 5. The method of claim 1, wherein the first fiducial data from the first fiducial comprises an image of the first fiducial received from the imaging device associated with the robot.
 6. A system comprising: a robot to perform one or more tasks in a workspace, the robot comprising: one or more imaging devices disposed on the robot to provide imagery of portions of the workspace proximate to the robot; a plurality of fiducials, each comprising fiducial data, attached to a floor in the workspace; and a cart to carry objects throughout the workspace, the cart associated with a worker and comprising: one or more imaging devices disposed on the cart to provide imagery of portions of the workspace proximate to the cart; a server in communication with the cart and the robot, the server receiving location information from the cart and the robot and establishing a barrier around the cart, wherein the server is external to the worker and the robot; wherein the server instructs the robot to take evasive action based at least in part on the robot crossing the barrier around the cart.
 7. The system of claim 6, wherein each of the plurality of fiducials comprises a radio frequency identification (RFID) tag, the RFID tag comprising at least one of location data or a fiducial identification number for each of the plurality of fiducials.
 8. The system of claim 6, wherein each of the plurality of fiducials comprises a bar code, the bar code comprising at least one of location data or a fiducial identification number for each of the plurality of fiducials.
 9. The system of claim 6, wherein the cart further comprises: a tether linking the worker to the cart; wherein a signal is sent to the server based at least in part on a distance detected by the tether between the worker and the cart exceeding a predetermined distance.
 10. The system of claim 9, the tether further comprising: a harness having a first end and a second end, the first end detachably coupleable to the worker and the second end detachably coupleable to a switch on the cart; wherein the harness detaches from the switch based at least in part on the distance between the worker and the cart exceeding the predetermined distance; and wherein the signal is sent to the server based at least in part on the harness detaching from the switch.
 11. The system of claim 9, the tether further comprising: a short range transmission tag coupled to a wearable device associated with the worker; and a short range transmission reader coupled to the cart and configured to read the short range transmission tag; wherein the signal is sent to the server based at least in part on the distance between the short range transmission tag and the short range transmission reader exceeding a range at which the short range transmission reader can read the short range transmission tag.
 12. The system of claim 11, wherein: the short range transmission tag comprises a radio frequency identification (RFID) tag; and the short range transmission reader comprises an RFID reader.
 13. The system of claim 6, wherein the server instructs the robot to take escalating evasive action as a distance between the robot and the cart decreases.
 14. The system of claim 6, wherein the server instructs the robot to at least one of: reroute based at least in part on a distance between the robot and the cart reaching a first predetermined distance; slow down based at least in part on the distance between the robot and the cart reaching a second predetermined distance; or stop based at least in part on the distance between the robot and the cart reaching a third predetermined distance.
 15. A method comprising: receiving, at a server from one or more robot imaging devices associated with a robot, first location information for the robot in a workspace; receiving, at the server from one or more cart imaging devices associated with a cart, second location information for the cart associated with a worker, wherein the server is external to the worker, the cart and the robot, the cart comprising: a carrying tray for carrying one or more objects; the one or more cart imaging devices to provide imagery proximate to the cart to the server; a wireless transceiver to provide wireless communication between the cart and the server; and a processor in communication with the one or more cart imaging devices and the wireless transceiver to send one or more signals to the server via the wireless transceiver; designating, with the server, a barrier encompassing at least the cart; and transmitting, from the server to the robot, an instruction to take evasive action based at least in part on the robot crossing the barrier.
 16. The method of claim 15, wherein the first location information for the robot comprises imagery data from the one or more robot imaging devices including fiducial data for one or more fiducials proximate to the robot.
 17. The method of claim 15, wherein the second location information for the cart comprises imagery from the one or more cart imaging devices including fiducial data for one or more fiducials proximate to the cart.
 18. The method of claim 15, wherein the cart further comprises: a tether to detect a distance between the worker and the cart exceeding a predetermined distance; the method further comprising: receiving a signal, at the server from the processor, based at least in part on the distance between the worker and the cart exceeding the predetermined distance; and sending, from the server to the robot, another instruction to stop based at least in part on the signal.
 19. The method of claim 18, further comprising: receiving, at the server from the processor, another signal based at least in part on the distance between the worker and the cart falling below the predetermined distance; and sending, from the server to the robot, a resume instruction to resume normal activity based at least in part on the another signal.
 20. The method of claim 18, wherein the tether comprises: one or more radio frequency identification (RFID) tags disposed on one of the worker or the cart; and an RFID reader disposed on the other of the worker or the cart; wherein the server receives the signal from the processor based at least in part on the RFID reader no longer reading at least one of the one or more RFID tags. 